Authorities say the 71-year-old from Selden wasn't wearing a life jacket when the high, fast-moving water Saturday near Sparrow Bush, about 65 miles northwest of New York City.
Crews searched through the day Sunday but found no sign of the man, whose name has not been released.
Officials tell the Times Herald-Record of Middletown that the man's wife, who was wearing a life jacket, jumped in and tried unsuccessfully to help him before he sank in water about 5 ½ feet deep. She and another person in the raft were rescued. They weren't injured.
The search is continuing Monday.